At left, Jonas Hall-Andersen, a volunteer from Denmark, helps regulate seating at a Bernie Sanders Get Out the Vote Rally at Franklin Pierce University Fieldhouse on February 4, 2016 in Rindge, New Hampshire.

For more than a year, my pragmatist friends and colleagues have underestimated the appeal of Bernie Sanders. As a big Sanders win approaches in the New Hampshire primary, they insist that this will be Sanders's last hurrah and urge his supporters to get real and get with the program—which is to unite behind Hillary Clinton as the Democrat best positioned to be nominated and to win in November.

Many of my political friends are simply missing the import of the Sanders campaign. Much of his appeal is a blend of generational and economic.

The millennial generation has gotten the worst economic screwing since the generation that came of age in the Great Depression. In some ways, their plight is worse, since in the Depression generation there was broad understanding that an economic catastrophe had occurred and it was correctly understood as political.

Until very recently, the plight of the millennials was seen as merely personal. Questions that should be, and are, deeply political have been taken as private problems—how to best cope with a bad economic environment; how to pick a shrewd career path given lousy choices. But it was only a matter of time before self-awareness of this reality finally took political form.

This is the first American generation ever to begin economic life deeply in debt. The entire premise that students should borrow large sums to attend college was horrible policy; it was never debated directly. Republicans are more responsible, because their budget cutting at the federal and state level shifted public financing onto tuition and fees. But both parties have colluded in the basic premise that borrowing to pay for college and starting life saddled with debt is an OK idea.

I've been wondering when college students and young adults would finally get into the streets to protest this appalling system. They are at last engaged in protest via the 2016 presidential campaign, and Sanders, who calls for debt-free higher education, is their champion.

And the debt for diploma system is only part of the story. This generation also faces a job market in which regularized employment is disappearing in favor of short-term gigs. For a time this could be romanticized as a rejection of materialism and an appreciation of the joys of flexibility. But that story got old.

Try being a 35-year-old, looking to buy a home and start a family on a series of gig jobs. The rate of homeownership among young adults has fallen precipitously because so many are too far in debt and too precarious in their employment to qualify for a mortgage.

Here again, Sanders much more than Clinton has been challenging an economy of, by, and for the rich—one that stunts the dreams of the young. At the heart of the skewed economy is the Wall Street domination of the rules of the game, and Sanders is the one willing to name that reality and call for its demolition.

The age gap in voters who supported Sanders versus Clinton in the Iowa Caucuses was the greatest recorded in political history. It is likely to be repeated in New Hampshire. This is not good news for Clinton or for those who insist on her inevitability.

My pragmatist friends make a number of arguments in their effort to dismiss the Sanders phenomenon.

First, Sanders is too left-wing to get nominated, much less elected. In principle he is, but this isn't a normal year. There is mass economic frustration in the land; it is finally, belatedly, the main issue in a presidential campaign; and it is up for grabs politically and ideologically. We can blame foreigners and government, or we can blame a badly tilted economic system.

If a Republican populist is nominated, a Democratic populist might well do better than a Democratic moderate in energizing the electorate and winning over working class voters who might otherwise support a figure like Donald Trump. It is not a good year to be the candidate who represents experience and continuity.

The polls show Sanders doing better than Clinton against the main Republican contenders. My pragmatist friends dismiss these on the grounds that the voters haven't really focused on Sanders's views yet, and the Republicans haven't yet opened up the heavy artillery.

Maybe so. But Clinton is also vulnerable as a Democratic nominee. She just has different vulnerabilities.

Then there is Sanders's age. He will be 75 on Election Day. It's surely paradoxical that the champion of the young is the oldest prospective nominee ever. My same pragmatist friends who think Sanders is too old are quick to embrace Joe Biden as a potential stand-in, should Clinton falter. And Biden is just a year younger than Sanders.

There is also the question of the political unreality of many of Sanders's proposals. His call for Medicare for All is both very expensive and inconceivable in a Congress where Republicans control even one chamber. I've written in a previous piece about how we might get to Medicare for All over time, by starting with 55-to-64-year-olds, then adding kids, and finally making a universal system politically irresistible and fiscally feasible.

But there are two good rejoinders to the contention that Sanders's proposals are too expensive and too unrealizable legislatively. For one thing, the greatest legislative successes of progressives—from Social Security to civil rights—started out at the fringe of practical politics and finally won enactment on the strength of political movements.

And, given the absolute intransigence of Republicans, does anyone think that the modest liberal proposals put forward by a Clinton would fare any better than far-reaching plans proposed by a Sanders? If there are any Republicans in Congress willing to cut Hillary Clinton any slack, I've missed them.

Last, there is the issue of Sanders's executive inexperience. My same pragmatist friends who make this criticism are the quickest to defend the record of Barack Obama, whose previous executive experience was four years running a Senate office no larger than Sanders's.

So maybe it's time to stop being so dismissive of Sanders and the mass frustration that he is channeling.

That said, Sanders is still the underdog. He still faces many primaries where Hillary Clinton is the overwhelming favorite. At 75, a self-proclaimed democratic socialist, not to mention a Jewish atheist, he is still an improbable nominee. That makes his momentum all the more remarkable and worth taking seriously.

The fact that Sanders is a force at all, that he is giving Clinton a real run for her money, suggests that that he represents something real and powerful in American politics—something that only a damned fool would dismiss.